1. Field of the Invention
The present invention relates to a water-hardenable dental cement composition.
A water-hardenable dental cement composition provided according to the present invention comprises hydroxyapatite as the main component and a specific inorganic powder and an unsaturated carboxylic acid or a copolymer of an unsaturated carboxylic acid with other organic compound. This dental cement composition is a new type of a dental cement. The dental composition of the present invention has a reduced irritation to the dental pulp cells and has an excellent reactivity with saliva.
2. Description of the Prior Art
Zinc phosphate cement and carboxylate cement have heretofore been used as the dental cement. These known cements, however, are defective and improvements have been desired. For example, zinc phosphate cement has a high compression strength but it is irritative to the dental pulp. Carboxylate cement is low in the compression strength and when it is formed into a cement liquid, the viscosity is too high and kneading is difficult.
Water-hardenable carboxylate cement has recently been developed, and this water-hardenable cement is improved over the known carboxylate cement in the operation adaptability and it shows an increased compression strength. However, this water-hardenable carboxylate cement is still insufficient in the reactivity with saliva.
Dental cement should satisfy the requirement that it should be kept in the form of a hardened body in the oral cavity without disintegration. All of the above-mentioned known cements are disintegrated in a short time if they fall in contact with saliva in the oral cavity, resulting in falling of repaired portions, and they are insufficient as permanent filling materials.
Under this background, development of dental cement having a high compression strength and an excellent operation adaptability and being capable of providing a hardened body which can be permanently maintained in good conditions without disintegration due to the action of saliva has been desired in the field of dental surgery, but this desire has not been satisfied.